When selecting R or S configuration, I know that we 1. Rank substituents by highest priority (highest atomic mass) 2. Find out which way priority is decreasing 3. If priority is decreasing clockwise, then R configuration… If priority is decreasing counterclockwise, then S configuration 4. Change R configuration to S configuration, or vice-versa, if lowest priority group is pointing to the front….. I understand all of this, however, I always get confused when the lowest priority group is neither pointing towards you or away from you…. Do we still flip the configuration if the lowest priority group is in the plane of the paper? (Flip the lowest in priority group, which is in the plane of paper with the group behind paper, determine configuration as usual, and flip your answer. - GS).   Or do we instead have to rotate the molecule in our minds in order to get the lowest priority facing away, and then go ahead and figure out the configuration?  Spasibo.  (This will also work.  Choose either method, depending on your individual strengths. - GS).  Your advice to flip the lowest priority, which is in the plane of paper, with the group behind the paper, determine configuration, and flip the answer sounds much better.  That really cleared things up.  Thank you!!